Zoom lens and image pickup apparatus having the same

ABSTRACT

A zoom lens includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a rear unit that includes a plurality of lens units having negative refractive powers and a plurality of lens units having positive refractive powers, each distance between adjacent lens units changing during zooming. During zooming from a wide-angle end to a telephoto end, the first lens unit moves to the object side, and the second lens unit moves to the image side and thereafter moves to the object side. A predetermined condition is satisfied.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The aspect of the embodiments relates to a zoom lens suitable for animage pickup apparatus such as a digital video camera, a digital stillcamera, a broadcasting camera, a silver halide film camera, and asurveillance camera.

Description of the Related Art

Zoom lenses used in image pickup apparatuses are required to be smalland to have high zoom ratios and high optical performance

Each of Japanese Patent Application Laid-Open Nos. (“JPs”) 2016-148731and 2013-235093 describes, as a zoom lens for realizing both a high zoomratio and high optical performance, a zoom lens including, in order froman object side to an image side, a first lens unit having a positiverefractive power, a second lens unit having a negative refractive power,a third lens unit having a positive refractive power, and a plurality oflens units.

However, although the zoom lenses of JPs 2016-148731 and 2013-235093 hasthe high zoom ratios and the high optical performance, they do notsatisfy the demands for small size. For realizing the small size, it isimportant to properly set a zoom type and a moving lens unit duringzooming.

SUMMARY OF THE DISCLOSURE

A zoom lens according to one aspect of the embodiments includes, inorder from an object side to an image side, a first lens unit having apositive refractive power, a second lens unit having a negativerefractive power, a third lens unit having a positive refractive power,and a rear unit that includes a plurality of lens units having negativerefractive powers and a plurality of lens units having positiverefractive powers, each distance between adjacent lens units changingduring zooming. During zooming from a wide-angle end to a telephoto end,the first lens unit moves to the object side, and the second lens unitmoves to the image side, and thereafter moves to the object side. Apredetermined condition is satisfied.

An image pickup apparatus including the above zoom lens also constitutesanother aspect of the embodiments.

Further features of the disclosure will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of lenses according to an Example 1 of thepresent disclosure.

FIGS. 2A to 2C are aberration diagrams at a wide-angle end (A), atmiddle (B), and at a telephoto end (C) when the zoom lens focuses on aninfinite distant object according to the Example 1 of the presentdisclosure.

FIG. 3 is a sectional view of lenses according to an Example 2 of thepresent disclosure.

FIGS. 4A to 4C are aberration diagrams at a wide-angle end (A), atmiddle (B), and at a telephoto end (C) when the zoom lens focuses on aninfinite distant object according to the Example 2 of the presentdisclosure.

FIG. 5 is a sectional view of lenses according to an Example 3 of thepresent disclosure.

FIGS. 6A to 6C are aberration diagrams at a wide-angle end (A), atmiddle (B), and at a telephoto end (C) when the zoom lens focuses on aninfinite distant object according to the Example 3 of the presentdisclosure.

FIG. 7 is a sectional view of lenses according to an Example 4 of thepresent disclosure.

FIGS. 8A to 8C are aberration diagrams at a wide-angle end (A), atmiddle (B), and at a telephoto end (C) when the zoom lens focuses on aninfinite distant object according to the Example 4 of the presentdisclosure.

FIG. 9 is a sectional view of lenses according to an Example 5 of thepresent disclosure.

FIGS. 10A to 10C are aberration diagrams at a wide-angle end (A), atmiddle (B), and at a telephoto end (C) when the zoom lens focuses on aninfinite distant object according to the Example 5 of the presentdisclosure.

FIG. 11 is a lateral aberration diagram at the telephoto end when thezoom lens performs image stabilization by 0.4 degrees, according to theExample 1 of the present disclosure.

FIG. 12 is a schematic diagram of a main part of an image pickupapparatus according to the present disclosure.

DESCRIPTION OF THE EMBODIMENTS

The zoom lens according to an embodiment of the present disclosureincludes, in order from an object side to an image side, a first lensunit B1 having a positive refractive power, i.e., an optical power whichis an inverse of a focal length, a second lens unit B2 having a negativerefractive power, a third lens unit B3 having a positive refractivepower, and a rear unit RL following on the image side and including aplurality of lens units having negative refractive powers and aplurality of lens units having positive refractive powers. Specifically,the rear unit RL includes, in order from the object side to the imageside, at least fourth to seventh lens units B4 to B7, each of which hasa positive or negative refractive power. Each distance between adjacentlens units changes during zooming.

In the zoom lens according to the embodiment of the present disclosure,during zooming from a wide-angle end to a telephoto end, the first lensunit B1 moves on an optical axis to the object side, and the second lensunit B2 moves on the optical axis to the image side and thereafter tothe object side.

The following expressions are satisfied:

5.50<f1/|f2|<7.50   (1)

0.56<m1/f1<1.19   (2)

where f1 represents a focal length of the first lens unit B1, f2represents a focal length of the second lens unit B2, and m1 representsa moving amount of the first lens unit B1 during zooming from thewide-angle end to the telephoto end. In this embodiment, a sign of themoving amount is assumed to be negative when a position of the firstlens unit B1 at the telephoto end is on the object side of that at thewide-angle end, and the sign of the moving amount is assumed to bepositive when the position of the first lens unit B1 at the telephotoend is on the image side of that at the wide-angle end.

When the above inequalities (1) and (2) are satisfied, it is possible torealize a zoom lens having both a high zoom ratio and good opticalperformance while having a small size.

The zoom lens according to the embodiment of the present disclosureincludes, in order from the object side to the image side, the firstlens unit having the positive refractive power, the second lens unithaving the strong negative refractive power, the third lens unit havingthe positive refractive power, and the rear unit including the pluralityof lens units. With such a configuration, both the high zoom ratio andthe high optical performance can be realized.

The zoom lens according to the embodiment of the present disclosureincludes the rear unit RL on the image side, and the rear unit includesthe plurality of negative lens units and the plurality of positive lensunits so that various aberrations are reduced while the zoom ratio ishigh.

In the zoom lens according to the embodiment of the present disclosure,during zooming from the wide-angle end to the telephoto end, the firstlens unit B1 moves on the optical axis to the object side, and thesecond lens unit B2 moves on the optical axis to the image side andthereafter to the object side. Thereby, both the high zoom ratio and thesmall size are realized.

The inequality (1) defines ranges of the focal length of the first lensunit B1 and the focal length of the second lens unit B2 by a ratiothereof. If the focal length of the first lens unit B1 is so large thatthe value is larger than the upper limit of the inequality (1),aberration is easily corrected, but the moving amount of a movable unitin the first lens unit B1 increases during zooming, making it difficultto reduce the size. If the focal length of the first lens unit B1 is sosmall that the value is smaller than the lower limit of the inequality(1), it is difficult to correct spherical aberration at the telephotoend.

The inequality (2) defines ranges of the moving amount of the first lensunit B1 from the wide-angle end to the telephoto end and the focallength of the first lens unit B1 by a ratio thereof. If the movingamount of the first lens unit B1 is so large that the value is largerthan the upper limit of the inequality (2), aberration is easilycorrected, but it is difficult to reduce the size. If the moving amountof the first lens unit B1 is so small that the value is smaller than thelower limit of the inequality (2), the size may be reduced, but it isparticularly difficult to correct spherical aberration at the telephotoend.

Focusing may be performed by the strongest negative lens unit in therear unit RL. The strongest negative lens unit in the rear unit RL islikely to have a relatively small diameter in the entire system, andthus the focusing driving apparatus can be made small.

Further, focusing may be performed by a sixth lens unit B6 having anegative refractive power so that various aberrations are corrected wellduring zooming.

A negative lens unit closest to a diaphragm in the rear unit RL may beused as an image stabilization lens unit by moving the lens unit in adirection including a component of a direction orthogonal to the opticalaxis during image stabilization. In the rear unit RL, the negative lensunit close to the diaphragm easily reduces aberration variation duringimage stabilization and is easily made to have a small diameter, andthus it is possible to realize a small-sized image stabilization drivingapparatus.

Image stabilization may be performed by a fourth lens unit B4 having anegative refractive power so that various aberrations are corrected wellduring image stabilization.

The following inequality may be satisfied:

2.71<fr/|f2|<6.53   (3)

where f2 represents the focal length of the second lens unit B2, and frrepresents a combined focal length of the rear unit RL at the wide-angleend.

The inequality (3) defines ranges of an absolute value of the focallength of the second lens unit B2 and the combined focal length of therear unit by a ratio thereof. If the absolute value of the focal lengthof the second lens unit B2 is so small that the value is larger than theupper limit of the inequality (3), a magnification variation amount iseasily ensured, but field curvature particularly increases at thewide-angle end. If the absolute value of the focal length of the secondlens unit B2 is so large that the value is smaller than the lower limitof the inequality (3), aberration is easily corrected, but a movingamount during zooming increases for ensuring a desired magnificationvariation amount, making it difficult to reduce the size.

The following inequality may be satisfied:

1.61<f1/f3<3.55   (4)

where f1 represents the focal length of the first lens unit B1, and f3represents a focal length of the third lens unit B3.

The inequality (4) defines ranges of the focal length of the first lensunit B1 and the focal length of the third lens unit B3 by a ratiothereof. If the focal length of the first lens unit B1 is so large thatthe value is larger than the upper limit of the inequality (4),aberration is easily corrected, but the moving amount of the first lensunit B1 during zooming increases for ensuring the desired magnificationvariation amount, making it difficult to reduce the size. If the focallength of the first lens unit B1 is so small that the value is smallerthan the lower limit of the inequality (4), the size may be reduced, butit is particularly difficult to correct spherical aberration at thetelephoto end.

The following inequality may be satisfied:

0.23<|f2|/f3<0.53   (5)

where f2 represents the focal length of the second lens unit B2 and f3represents the focal length of the third lens unit B3.

The inequality (5) defines ranges of the absolute value of the focallength of the second lens unit B2 and the focal length of the third lensunit B3 by a ratio thereof. If the focal length of the third lens unitB3 is so small that the value is larger than the upper limit of theinequality (5), aberration is easily corrected, but a moving amount ofthe third lens unit B3 during zooming increases for ensuring the desiredmagnification variation amount, making it difficult to reduce the size.If the focal length of the third lens unit B3 is so large that the valueis smaller than the lower limit of the inequality (5), the size may bereduced, but it is particularly difficult to correct sphericalaberration at the telephoto end.

The following inequality may be satisfied:

0.38<f2/ff<1.02   (6)

where ff represents a focal length of a lens unit having the strongestnegative refractive power in the rear unit RL, i.e., a lens unit havinga focal length of the smallest absolute value in the plurality of lensunits having the negative refractive powers included in the rear unitRL, and f2 represents the focal length of the second lens unit B2.

The inequality (6) defines ranges of the focal length of the lens unithaving the strongest negative refractive power in the rear unit RL,which performs focusing, and the focal length of the second lens unit B2by a ratio thereof. If the focal length of the second lens unit B2 is solarge that the value is larger than the upper limit of the inequality(6), the desired magnification variation amount is easily ensured, butit is particularly difficult to correct field curvature at thewide-angle end. If the focal length of the second lens unit B2 is sosmall that the value is smaller than the lower limit of the inequality(6), aberration is easily corrected, but the moving amount duringzooming increases for ensuring the desired magnification variationamount, making it difficult to reduce the size.

The following inequality may be satisfied:

0.62<|f2|/skw<1.60   (7)

where f2 represents the focal length of the second lens unit B2, skwrepresents a back focus at the wide-angle end.

The inequality (7) defines ranges of the absolute value of the focallength of the second lens unit B2 and the back focus at the wide-angleend by the ratio thereof. If the absolute value of the focal length ofthe second lens unit B2 is so large that the value is larger than theupper limit of the inequality (7), the desired magnification variationamount is easily ensured, but it is particularly difficult to correctfield curvature at the wide-angle end. If the absolute value of thefocal length of the second lens unit B2 is so small that the value issmaller than the lower limit of the inequality (7), aberration is easilycorrected, but the moving amount during zooming increases for ensuringthe desired magnification variation amount, making it difficult toreduce the size.

The following inequality may be satisfied:

1.70<f3/skw<4.39   (8)

where f3 represents the focal length of the third lens unit B3 and skwrepresents the back focus at the wide-angle end.

The inequality (8) defines ranges the focal length of the third lensunit B3 and the back focus at the wide-angle end by a ratio thereof. Ifthe focal length of the third lens unit B3 is so large that the value islarger than the upper limit of the inequality (8), the desiredmagnification variation amount is easily ensured, but it is particularlydifficult to correct spherical aberration at the telephoto end. If thefocal length of the third lens unit B3 is so small that the value issmaller than the lower limit of the inequality (8), aberration is easilycorrected, but the moving amount during zooming increases for ensuringthe desired magnification variation amount, making it difficult toreduce the size.

The following inequality may be satisfied:

0.17<f2/fsi<0.38   (9)

where f2 represents the focal length of the second lens unit B2, and fsirepresents the focal length of the lens unit having the negativerefractive power closest to the diaphragm in the rear unit RL.

The inequality (9) defines ranges of the focal length of the second lensunit B2 and the focal length of the lens unit having the negativerefractive power closest to the diaphragm in the rear unit RL, whichperforms image stabilization, by a ratio thereof. If the focal length ofthe second lens unit B2 is so large that the value is larger than theupper limit of the inequality (9), the size may be reduced, but it isparticularly difficult to correct field curvature at the wide-angle end.If the focal length of the second lens unit B2 is so small that thevalue is smaller than the lower limit of the inequality (9), aberrationis easily corrected, but the moving amount during zooming increases forensuring the desired magnification variation amount, making it difficultto reduce the size.

The following inequality may be satisfied:

0.26<f1/ft<0.54   (10)

where f1 represents the focal length of the first lens unit B1, and ftrepresents a focal length of the entire system at the telephoto end.

The inequality (10) defines ranges of the focal length of the first lensunit B1 and the focal length of the entire system at the telephoto endby a ratio thereof. If the focal length of the first lens unit B1 is solarge that the value is larger than the upper limit of the inequality(10), aberration is easily corrected, but the moving amount of the firstlens unit B1 during zooming increases for ensuring the desiredmagnification variation amount, making it difficult to reduce the size.If the focal length of the first lens unit B1 is so small that the valueis smaller than the lower limit of the inequality (10), the size may bereduced, but it is particularly difficult to correct sphericalaberration at the telephoto end.

The following inequality may be satisfied:

0.72<|f2|/fw<1.67   (11)

where f2 represents the focal length of the second lens unit B2, and fwrepresents a focal length of the entire system at the wide-angle end.

The inequality (11) defines ranges of the absolute value of the focallength of the second lens unit B2 and the focal length of the entiresystem at the wide-angle end by a ratio thereof. If the absolute valueof the focal length of the second lens unit B2 is so large that thevalue is larger than the upper limit of the inequality (11), the desiredmagnification variation amount is easily ensured, but it is particularlydifficult to correct field curvature at the wide-angle end. If theabsolute value of the focal length of the second lens unit B2 is sosmall that the value is smaller than the lower limit of the inequality(11), aberration is easily corrected, but the moving amount duringzooming increases for ensuring the desired magnification variationamount, making it difficult to reduce the size.

The following inequality may be satisfied:

0.11<f3/ft<0.24   (12)

where f3 represents the focal length of the third lens unit B3 and ftrepresents the focal length of the entire system at the telephoto end.

The inequality (12) defines ranges of the focal length of the third lensunit B3 and the focal length of the entire system at the telephoto endby a ratio thereof. If the focal length of the third lens unit B3 is solarge that the value is larger than the upper limit of the inequality(12), aberration is easily corrected, but the moving amount of the firstlens unit B1 during zooming increases for ensuring the desiredmagnification variation amount, making it difficult to reduce the size.If the focal length of the third lens unit B3 is so small that the valueis smaller than the lower limit of the inequality (12), the size may bereduced, but it is particularly difficult to correct sphericalaberration at the telephoto end.

The second lens unit B2 may include two or more positive lenses andthree or more negative lenses so that lateral chromatic aberration andon-axis chromatic aberration are corrected well.

The second lens unit B2 may include two positive lenses and four or morenegative lenses.

Each lens may move on the optical axis during zooming so as to reduceaberration variation. During zooming from the wide-angle end to thetelephoto end, all the lens units in the rear unit RL may move to theobject side along the optical axis.

The rear unit RL may include a fifth lens unit B5 having a positiverefractive power and a seventh lens unit B7 having a positive refractivepower so that aberration is corrected well.

The numerical ranges of the inequalities (1) to (12) may be set asfollows.

5.80<f1/|f2|<7.21   (1a)

0.67<m1/f1<1.02   (2a)

3.25<fr/|f2|<5.60   (3a)

1.93<f1/f3<3.04   (4a)

0.28<|f2|/f3<0.45   (5a)

0.46<f2/ff<0.87   (6a)

0.75<|f2|/skw<1.37   (7a)

2.04<f3/skw<3.76   (8a)

0.21<f2/fsi<0.33   (9a)

0.31<f1/ft<0.46   (10a)

0.86<|f2|/fw<1.43   (11a)

0.13<f3/ft<0.20   (12a)

The numerical ranges of the inequalities (1a) to (12a) may be set asfollows.

6.18<f1/|f2|<6.99   (1b)

0.75<m1/f1<0.89   (2b)

3.66<fr/|f2|<4.90   (3b)

2.18<f1/f3<2.66   (4b)

0.31<|f2|/f3<0.40   (5b)

0.52<f2/ff<0.76   (6b)

0.84<|f2|/skw<1.20   (7b)

2.30<f3/skw<3.29   (8b)

0.23<f2/fsi<0.29   (9b)

0.35<f1/ft<0.41   (10b)

0.97<|f2|/fw<1.25   (11b)

0.14<f3/ft<0.18   (12b)

As described above, the zoom lens according to the embodiment of thepresent disclosure can realize a small-sized zoom lens having a highzoom ratio and good optical performance over the entire zoom range fromthe wide-angle end to the telephoto end.

Examples of the present disclosure will be described in detail belowbased on the attached drawings.

EXAMPLE 1

FIG. 1 illustrates a sectional view of lenses at a wide-angle end, i.e.,a short focal length end, and at a telephoto end, i.e., a long focallength end, of a zoom lens according to an Example 1 of the presentdisclosure.

FIGS. 2A to 2C are aberration diagrams at the wide-angle end, middlezoom position, and telephoto end when the zoom lens of the Example 1focuses on an infinite distant object, respectively.

The zoom lens of the Example 1 has a high zoom ratio of about 19 times.The zoom lens of the Example 1 includes, in order from an object side toan image side, a first lens unit B1 having a positive refractive power,a second lens unit B2 having a negative refractive power, a third lensunit B3 having a positive refractive power, and a rear unit RL followingon the image side. The rear unit RL includes three lens units havingnegative refractive powers and two lens units having positive refractivepowers. Specifically, the rear unit RL includes a fourth lens unit B4having a negative refractive power, a fifth lens unit B5 having apositive refractive power, a sixth lens unit B6 having a negativerefractive power, a seventh lens unit B7 having a positive refractivepower, and an eighth lens unit B8 having a negative refractive power.During zooming, the first lens unit B1 moves to the object side from thewide-angle end to the telephoto end, the second lens unit B2 moves on anoptical axis to the image side, and then moves to the object side, fromthe wide-angle end to the telephoto end, and the rear unit RL alsoproperly moves.

In the rear unit RL, a lens unit having a negative refractive powerclosest to a diaphragm corresponds to the fourth lens unit B4, and imagestabilization is performed by moving the fourth lens unit B4 in adirection including a component of a direction orthogonal to the opticalaxis.

A lens unit having the strongest negative refractive power in the rearunit RL corresponds to the sixth lens unit B6, and focusing is performedby moving the sixth lens unit B6 along the optical axis. The diaphragmis disposed between the second lens unit B2 and the third lens unit B3.

EXAMPLE 2

FIG. 3 illustrates a sectional view of lenses at a wide-angle end, i.e.,a short focal length end, and at a telephoto end, i.e., a long focallength end, of a zoom lens according to an Example 2 of the presentdisclosure.

FIGS. 4A to 4C are aberration diagrams at the wide-angle end, middlezoom position, and telephoto end when the zoom lens of the Example 2focuses on an infinite distant object, respectively.

The zoom lens of the Example 2 has a high zoom ratio of about 19 times.The zoom lens of the Example 2 includes, in order from an object side toan image side, a first lens unit B1 having a positive refractive power,a second lens unit B2 having a negative refractive power, a third lensunit B3 having a positive refractive power, and a rear unit RL followingon the image side. The rear unit RL includes two lens units havingnegative refractive powers and two lens units having positive refractivepowers. Specifically, the rear unit RL includes a fourth lens unit B4having a negative refractive power, a fifth lens unit B5 having apositive refractive power, a sixth lens unit B6 having a negativerefractive power, and a seventh lens unit B7 having a positiverefractive power. During zooming, the first lens unit B1 moves to theobject side from the wide-angle end to the telephoto end, the secondlens unit B2 moves on an optical axis to the image side, and then movesto the object side, from the wide-angle end to the telephoto end, andthe rear unit RL also properly moves.

In the rear unit RL, a lens unit having a negative refractive powerclosest to a diaphragm corresponds to the fourth lens unit B4, and imagestabilization is performed by moving the fourth lens unit B4 in adirection including a component of a direction orthogonal to the opticalaxis.

A lens unit having the strongest negative refractive power in the rearunit RL corresponds to the sixth lens unit B6, and focusing is performedby moving the sixth lens unit B6 along the optical axis. The diaphragmis disposed between the second lens unit B2 and the third lens unit B3.

EXAMPLE 3

FIG. 5 illustrates a sectional view of lenses at a wide-angle end, i.e.,a short focal length end, and at a telephoto end, i.e., a long focallength end, of a zoom lens according to an Example 3 of the presentdisclosure.

FIGS. 6A to 6C are aberration diagrams at the wide-angle end, middlezoom position, and telephoto end when the zoom lens of the Example 3focuses on an infinite distant object, respectively.

The zoom lens of the Example 3 has a high zoom ratio of about 19 times.The zoom lens of the Example 3 includes a first lens unit B1 having apositive refractive power, a second lens unit B2 having a negativerefractive power, a third lens unit B3 having a positive refractivepower, and a rear unit RL following on the image side. The rear unit RLincludes three lens units having negative refractive powers and threelens units having positive refractive powers. Specifically, the rearunit RL includes a fourth lens unit B4 having a negative refractivepower, a fifth lens unit B5 having a positive refractive power, a sixthlens unit B6 having a negative refractive power, a seventh lens unit B7having a positive refractive power, an eighth lens unit B8 having anegative refractive power, and a ninth lens unit B9 having a positiverefractive power. During zooming, the first lens unit B1 moves to theobject side from the wide-angle end to the telephoto end, the secondlens unit B2 moves on an optical axis to the image side, and then movesto the object side, from the wide-angle end to the telephoto end, andthe rear unit RL also properly moves.

In the rear unit RL, a lens unit having a negative refractive powerclosest to a diaphragm corresponds to the fourth lens unit B4, and imagestabilization is performed by moving the fourth lens unit B4 in adirection including a component of a direction orthogonal to the opticalaxis.

A lens unit having the strongest negative refractive power in the rearunit RL corresponds to the sixth lens unit B6, and focusing is performedby moving the sixth lens unit B6 along the optical axis. The diaphragmis disposed between the second lens unit B2 and the third lens unit B3.

EXAMPLE 4

FIG. 7 illustrates a sectional view of lenses at a wide-angle end, i.e.,a short focal length end, and at a telephoto end, i.e., a long focallength end, of a zoom lens according to an Example 4 of the presentdisclosure.

FIGS. 8A to 8C are aberration diagrams at the wide-angle end, middlezoom position, and telephoto end when the zoom lens of the Example 4focuses on an infinite distant object, respectively.

The zoom lens of the Example 4 has a high zoom ratio of about 19 times.The zoom lens of the Example 4 includes a first lens unit B1 having apositive refractive power, a second lens unit B2 having a negativerefractive power, a third lens unit B3 having a positive refractivepower, and a rear unit RL following on the image side. The rear unit RLincludes two lens units having negative refractive powers and three lensunits having positive refractive powers. Specifically, the rear unit RLincludes a fourth lens unit B4 having a negative refractive power, afifth lens unit B5 having a positive refractive power, a sixth lens unitB6 having a negative refractive power, a seventh lens unit B7 having apositive refractive power, and an eighth lens unit B8 having a positiverefractive power. During zooming, the first lens unit B1 moves to theobject side from the wide-angle end to the telephoto end, the secondlens unit B2 moves on an optical axis to the image side, and then movesto the object side, from the wide-angle end to the telephoto end, andthe rear unit RL also properly moves.

In the rear unit RL, a lens unit having a negative refractive powerclosest to a diaphragm corresponds to the fourth lens unit B4, and imagestabilization is performed by moving the fourth lens unit B4 in adirection including a component of a direction orthogonal to the opticalaxis.

A lens unit having the strongest negative refractive power in the rearunit RL corresponds to the sixth lens unit B6, and focusing is performedby moving the sixth lens unit B6 along the optical axis. The diaphragmis disposed between the second lens unit B2 and the third lens unit B3.

EXAMPLE 5

FIG. 9 illustrates a sectional view of lenses at a wide-angle end, i.e.,a short focal length end, and at a telephoto end, i.e., a long focallength end, of a zoom lens according to an Example 5 of the presentdisclosure.

FIGS. 10A to 10C are aberration diagrams at the wide-angle end, middlezoom position, and telephoto end when the zoom lens of the Example 5focuses on an infinite distant object, respectively.

The zoom lens of the Example 5 has a high zoom ratio of about 19 times.The zoom lens of the Example 5 includes a first lens unit B1 having apositive refractive power, a second lens unit B2 having a negativerefractive power, a third lens unit B3 having a positive refractivepower, and a rear unit RL following on the image side. The rear unit RLincludes three lens units having negative refractive powers and threelens units having positive refractive powers. Specifically, the rearunit RL includes a fourth lens unit B4 having a negative refractivepower, a fifth lens unit B5 having a positive refractive power, a sixthlens unit B6 having a negative refractive power, a seventh lens unit B7having a positive refractive power, an eighth lens unit B8 having anegative refractive power, and a ninety lens unit B9 having a positiverefractive power. During zooming, the first lens unit B1 moves to theobject side from the wide-angle end to the telephoto end, the secondlens unit B2 moves on an optical axis to the image side, and then movesto the object side, from the wide-angle end to the telephoto end, andthe rear unit RL also properly moves.

In the rear unit RL, a lens unit having a negative refractive powerclosest to a diaphragm corresponds to the fourth lens unit B4, and imagestabilization is performed by moving the fourth lens unit B4 in adirection including a component of a direction orthogonal to the opticalaxis.

A lens unit having the strongest negative refractive power in the rearunit RL corresponds to the sixth lens unit B6, and focusing is performedby moving the sixth lens unit B6 along the optical axis. The diaphragmis disposed between the second lens unit B2 and the third lens unit B3.

FIG. 11 illustrates lateral aberration diagrams in a state where thefourth lens unit B4 of the Example 1 of the present disclosure is madeparallely eccentric and an angle of the optical axis on the objectsurface is changed by about 0.4 degrees so that image stabilization isperformed by the fourth lens unit B4. In the other examples, imagestabilization can be performed by the fourth lens unit B4.

The zoom lens of each example is an image pickup lens system used for animage pickup apparatus such as a video camera, a digital still camera, asilver-halide film camera, and a TV camera.

The zoom lens of each example can also be used as a projection opticalsystem for a projection apparatus.

In each sectional view of lenses, a left side is the object side, i.e.,a front side, and a right side is the image side, i.e., a rear side. Ineach sectional view of lenses, when i is an order of a lens unit countedfrom the object side, Bi represents an i-th lens unit. In each sectionalview of lenses, partial units included in the first lens unit B1 are afirst partial unit B1A and a second partial unit B1B, in order from theobject side.

In each sectional view of lenses, FL represents a focus lens unit, and adotted arrow indicates an extension direction from an infinite side to aclose side. SP represents the diaphragm. GB represents an optical blockcorresponding to an optical filter, a face plate, a low-pass filter, aninfrared cut filter, and the like. IP represents an image plane. Theimage plane IP corresponds to an image pickup plane of an image sensor,which is a photoelectric conversion element, such as a CCD sensor and aCMOS sensor when the zoom lens is used as an image pickup optical systemof a video camera or a digital camera. The image plane IP corresponds toa film surface when the zoom lens is used as an image pickup opticalsystem of a silver-halide film camera.

A solid arrow represents a moving trajectory of each lens unit duringzooming from the wide-angle end to the telephoto end. Each distancebetween adjacent lens units changes during zooming.

In aberration diagrams of each example, Fno represents a F number and ωrepresents a half angle of view (°). In each spherical aberrationdiagram, a solid line represents a d line of a wavelength of 587.6 nmand an alternate long and short dash line represents a g line of awavelength of 435.8 nm. In each astigmatism diagram, a solid linerepresents a sagittal image plane ΔS for the d line, and a dotted linerepresents a meridional image plane ΔM for the d line. Each distortiondiagram is for the d line. Each lateral chromatic aberration diagram isfor the g-line.

In each example, the wide-angle end and telephoto end refer to zoompositions when the lens unit for zooming is located at both ends of amechanically movable range on the optical axis.

The lateral aberration diagrams of FIG. 11 describe aberrationvariations in a state where image stabilization is performed, for acenter of an image height and upper and lower image heights. Each solidline represents lateral chromatic aberration ΔM of meridional for the dline, and each dotted line represents lateral aberration ΔS of sagittal.Numerical values indicated as HGT in FIG. 11 correspond to off-axisimage heights, +15 mm corresponds to the upper side of the sectionalview, and −15 mm corresponds to the lower side of the sectional view.

Image Pickup Apparatus

Next, a description will be given of an embodiment of a digital cameraas an image pickup apparatus using the zoom lens according to theembodiment of the present disclosure as the image pickup optical systemwith reference to FIG. 12. FIG. 12 is a schematic view illustrating amain part of the digital still camera as the image pickup apparatushaving the zoom lens according to the embodiment of present disclosure.

In FIG. 12, a reference numeral 20 denotes a digital camera main body,and a reference numeral 21 denotes an image pickup optical systemincluding the zoom lens of any of the above Examples. A referencenumeral 22 denotes an image sensor as a photoelectric conversionelement, such as a CCD configured to receive light of an object imagefrom the image pickup optical system 21. A reference numeral 23 denotesa memory configured to store the object image received from the imagesensor 22. A reference numeral 24 denotes a finder for observing theobject image displayed on a display element (not illustrated).

The display element includes a liquid crystal panel, etc., and isconfigured to display the object image formed on the image sensor 22.When the zoom lens according to the embodiment of the present disclosureis applied to the image pickup apparatus such as the digital camera inthis way, it is possible to provide a small-sized image pickup apparatushaving high optical performance

Following Numerical Examples 1 to 5 describes specific numerical datacorresponding to the Examples 1 to 5. In each numerical example, irepresents a surface number counted from the object side. fi representsa focal length of an i-th lens unit. ri represents a curvature radius ofan i-th optical surface. di represents an on-axis distance between thei-th surface and a (i+1)-th surface. ndi and νdi respectively representa refractive index and an Abbe number of material of the i-th opticalelement for the d line. Two surfaces on the most image side correspondto a glass block G. An Abbe number νd of certain material is representedby

νd=(Nd−1)/(NF−NC)

where Nd, NF, and NC represent refractive indexes for the d line (587.6nm), F line (486.1 nm), and C line (656.3 nm) of Fraunhofer lines,respectively,

In each numerical example, d, focal length (mm), F number, and halfangle of view (°) are all values when the optical system of each examplefocuses on an infinite distant object. “Back focus BF” is a distance onthe optical axis from a lens last surface, which is a lens surface onthe most image side, to a paraxial image plane, expressed as an airconversion length. “Overall lens length” is a sum of a distance on theoptical axis from a front surface of the zoom lens, which is a lenssurface on the most object side, to the last surface, and the backfocus. Wide-angle indicates the wide-angle end, middle indicates themiddle zoom position, and telephoto indicates the telephoto end.

When an optical surface is an aspherical surface, a * sign is attachedto the right side of the surface number. An aspherical surface shape isexpressed by the following expression:

x=(h ² /R)/[1+{1−(1+k)(h/R)²}^(1/2) +A4×h ⁴ +A6×h ⁶ +A8×h ⁸ +A10×h ¹⁰+A12×h ¹²

where X represents an amount of displacement from a surface vertex inthe optical axis direction, h represents a height from the optical axisin the direction orthogonal to the optical axis, R represents a paraxialcurvature radius, k represents a conic constant, A4, A6, A8, A10, andA12 represent aspherical surface coefficients of respective orders. “e±XX” in each aspherical surface coefficient represents “×10±^(XX)”.

[NUMERICAL EXAMPLE 1] Unit: mm Surface number r d nd vd SURFACE DATA  1∞ 1.80  2 216.778 4.00 1.80610 33.3  3 132.288 11.30 1.49700 81.5  4−3138.961 0.20  5 131.079 7.91 1.49700 81.5  6 559.185 (variable)  7238.370 2.40 1.89190 37.1  8 30.381 10.55  9 −155.284 2.00 1.89190 37.110 82.883 0.20 11 68.878 9.65 1.84666 23.8 12 −58.288 0.20 13 −65.9482.00 1.89190 37.1 14 99.320 0.20 15 63.239 6.01 1.72825 28.5 16 −237.9492.04 1.90366 31.3 17 445.526 (variable) 18 (diaphragm) ∞ 1.50 19 45.5675.03 1.78472 25.7 20 −324.029 0.20 21 32.837 6.32 1.49700 81.5 22−122.651 1.45 1.85478 24.8 23 32.292 (variable) 24 −97.276 4.06 1.6073856.8 25 −28.119 1.35 1.59522 67.7 26 307.771 (variable) 27 143.558 4.161.72000 46.0 28 −62.468 0.20 29 53.287 6.14 1.59522 67.7 30 −44.734 1.501.90366 31.3 31 −337.425 (variable) 32 -88.970 5.20 1.84666 23.8 33−24.825 1.30 1.80610 33.3 34 85.062 (variable) 35 146.359 1.60 1.8051825.4 36 82.298 5.34 1.53172 48.8 37 −86.332 0.31 38 256.759 3.50 1.5174252.2 39 −110.200 (variable) 40 −63.946 1.60 1.88202 37.2 41 50.834 7.211.74077 27.8 42 −352.595 (variable) 43 ∞ 2.00 1.51633 64.1 44 ∞(variable) Image Plane ∞ VARIOUS DATA Zoom Ratio 19.18 Wide- Tele- AngleMiddle photo Focal Length: 30.50 300.00 585.00 Fno: 4.00 6.76 8.00 HalfAngle of View (°): 35.35 4.12 2.12 Image Height: 21.64 21.64 21.64Overall Lens Length: 309.33 427.20 489.09 BF: 29.33 69.05 102.45 d 61.20 130.62 149.77 d17 97.47 12.22 2.21 d23 5.35 14.21 19.89 d26 16.587.72 2.03 d31 2.69 7.01 2.69 d34 24.92 43.53 68.62 d39 13.37 24.43 23.01d42 26.88 66.60 100.00 d44 1.13 1.13 1.13 Starting Focal Lens UnitSurface Length ZOOM LENS UNIT DATA 1 1 225.80 2 7 −33.60 3 18 91.96 4 24−128.56 5 27 42.29 6 32 −56.75 7 35 67.68 8 40 −69.76 9 43 ∞

[NUMERICAL EXAMPLE 2] Unit: mm Surface number r d nd vd SURFACE DATA  1∞ 1.80  2 188.901 4.00 1.80610 33.3  3 120.086 11.40 1.49700 81.5  41867.591 0.20  5 134.277 8.04 1.49700 81.5  6 825.900 (variable)  7294.228 2.40 1.88300 40.8  8 30.173 12.00  9 −76.540 2.00 1.88300 40.810 176.969 0.20 11 114.152 8.00 1.84666 23.8 12 −61.516 0.20 13 −77.6932.00 1.89190 37.1 14 158.995 0.20 15 77.336 6.01 1.67270 32.1 16−166.138 2.00 1.89190 37.1 17 −357.013 (variable) 18 (diaphragm) ∞ 1.5019 42.383 4.79 1.85478 24.8 20 5689.634 0.20 21* 35.365 5.68 1.4970081.5 22 −218.398 1.45 1.84666 23.8 23 30.749 (variable) 24 −91.776 2.811.65844 50.9 25 −40.443 1.30 1.59522 67.7 26 349.809 (variable) 27118.743 3.98 1.69100 54.8 28 −75.539 0.20 29 58.391 6.32 1.59522 67.7 30−40.419 1.50 1.90366 31.3 31 −151.366 (variable) 32 −109.232 5.201.90366 31.3 33 −24.664 1.30 1.85150 40.8 34 87.557 (variable) 35119.777 1.60 1.84666 23.8 36 74.154 5.70 1.53172 48.8 37 −143.703 0.2038 452.277 3.50 1.51823 58.9 39 −91.835 10.96 40 −73.186 1.60 1.8515040.8 41 45.093 6.28 1.74077 27.8 42 −352.595 (variable) 43 ∞ 2.001.51633 64.1 44 ∞ (variable) Image Plane ∞ ASPHERICAL SURFACE DATA 21stsurface K = 0.00000e+000 A4 = −5.87534e−007 A6 = −3.33478e−010 A8 =−1.17968e−012 VARIOUS DATA Zoom Ratio 19.18 Wide-Angle Middle TelephotoFocal Length: 30.50 302.00 585.00 Fno: 4.00 6.76 8.00 Half Angle of View(°): 35.35 4.10 2.12 Image Height: 21.64 21.64 21.64 Overall LensLength: 309.33 431.61 489.33 BF: 35.46 94.70 102.45 d 6 1.20 126.39144.72 d17 97.23 17.29 2.00 d23 5.76 19.65 24.16 d26 20.41 6.52 2.00 d312.22 4.14 2.36 d34 20.54 36.39 85.10 d42 33.01 92.26 100.00 d44 1.131.13 1.13 Lens Unit Starting Surface Focal Length ZOOM LENS UNIT DATA 11 222.09 2 7 −36.40 3 18 98.44 4 24 −136.57 5 27 42.90 6 32 −62.12 7 35312.95 8 43 ∞

[NUMERICAL EXAMPLE 3] Unit: mm Surface number r d nd vd SURFACE DATA  1∞ 1.80  2 223.463 4.00 1.80610 33.3  3 133.187 11.47 1.49700 81.5  4−1959.031 0.20  5 126.710 8.05 1.49700 81.5  6 530.754 (variable)  7189.567 2.40 1.88300 40.8  8 28.256 11.35  9 −124.138 2.00 1.88300 40.810 122.879 0.20 11 64.284 8.71 1.84666 23.8 12 −74.483 0.20 13 −79.3902.00 1.89190 37.1 14 98.962 0.20 15 70.205 6.01 1.67270 32.1 16 −150.6392.00 1.89190 37.1 17 902.370 (variable) 18 (diaphragm) ∞ 1.50 19 52.5344.42 1.85478 24.8 20 −373.094 0.20 21* 34.325 6.56 1.49700 81.5 22−183.232 1.82 1.84666 23.8 23 34.368 (variable) 24 −93.156 2.84 1.6584450.9 25 −40.085 1.30 1.59522 67.7 26 297.349 (variable) 27 216.877 3.681.69100 54.8 28 −67.658 0.20 29 47.104 6.62 1.59522 67.7 30 −42.486 1.501.90366 31.3 31 −153.552 (variable) 32 −106.102 5.07 1.90366 31.3 33−24.067 1.30 1.85150 40.8 34 73.203 (variable) 35 327.023 1.60 1.8466623.8 36 150.439 3.57 1.53172 48.8 37 −119.144 0.20 38 148.328 3.501.51823 58.9 39 −169.036 (variable) 40 −145.716 1.60 1.83400 37.3 4141.303 3.91 1.74077 27.8 42 119.417 (variable) 43 136.097 1.60 1.9036631.3 44 49.860 4.96 1.74077 27.8 45 −838.454 (variable) 46 ∞ 2.001.51633 64.1 47 ∞ (variable) Image Plane ∞ ASPHERICAL SURFACE DATA 21stsurface K = 0.00000e+000 A4 = −9.09245e−008 A6 = 1.13476e−010 A8 =−6.46254e−013 VARIOUS DATA Zoom Ratio 19.18 Wide-Angle Middle TelephotoFocal Length: 30.50 302.00 585.00 Fno: 4.00 6.76 8.00 Half Angle of View(°): 35.35 4.10 2.12 Image Height: 21.64 21.64 21.64 Overall LensLength: 311.33 424.37 487.84 BF 36.69 74.87 96.76 d 6 1.20 124.37 145.66d17 95.86 9.66 3.11 d23 5.92 19.85 26.23 d26 22.44 8.51 2.13 d31 2.253.60 2.25 d34 18.66 27.29 63.88 d39 7.65 32.31 22.77 d42 2.14 5.39 6.53d45 34.26 72.43 94.33 d47 1.12 1.12 1.12 Lens Unit Starting SurfaceFocal Length ZOOM LENS UNIT DATA  1 1 221.60  2 7 −32.93  3 18 87.50  424 −133.21  5 27 40.75  6 32 −54.80  7 35 87.57  8 40 −69.75  9 43234.68 10 46 ∞

[NUMERICAL EXAMPLE 4] Unit: mm Surface number r d nd vd SURFACE DATA  1∞ 1.80  2 194.406 4.00 1.80610 33.3  3 124.165 11.36 1.49700 81.5  46070.305 0.20  5 135.830 8.19 1.49700 81.5  6 665.019 (variable)  7268.674 2.40 1.89190 37.1  8 30.253 11.04  9 −115.334 2.00 1.89190 37.110 97.319 0.20 11 74.522 9.85 1.84666 23.8 12 −53.753 0.21 13 −57.4362.00 1.85150 40.8 14 109.786 0.21 15 70.054 6.01 1.64769 33.8 16−181.773 2.00 1.90366 31.3 17 −504.471 (variable) 18 (diaphragm) ∞ 1.5019 43.992 4.79 1.78472 25.7 20 −669.611 0.20 21 32.308 6.08 1.49700 81.522 −193.258 1.45 1.85478 24.8 23 31.277 (variable) 24 −95.631 2.991.65100 56.2 25 −38.121 1.30 1.59522 67.7 26 247.918 (variable) 27126.296 3.98 1.72000 46.0 28 −68.604 0.20 29 50.825 6.32 1.59522 67.7 30−40.817 1.50 1.90366 31.3 31 −226.260 (variable) 32 −80.833 5.20 1.8466623.8 33 −22.584 1.30 1.80610 33.3 34 68.959 (variable) 35 148.711 1.601.80518 25.4 36 89.855 5.66 1.53172 48.8 37 −66.961 0.20 38 254.798 3.501.69350 50.8 39 −111.810 10.06 40 −76.621 1.60 1.89190 37.1 41 53.6983.33 1.74077 27.8 42 147.053 (variable) 43 209.982 1.60 1.85883 30.0 4461.738 4.47 1.74077 27.8 45 −401.314 (variable) 46 ∞ 2.00 1.51633 64.147 ∞ (variable) Image Plane ∞ VARIOUS DATA Zoom Ratio 19.18 Wide- Tele-Angle Middle photo Focal Length: 30.50 302.00 585.00 Fno: 4.00 6.76 8.00Half Angle of View (°): 35.35 4.10 2.12 Image Height: 21.64 21.64 21.64Overall Lens Length: 311.33 428.68 485.25 BF: 34.87 79.87 100.91 d 61.20 130.90 147.97 d17 97.73 16.40 2.00 d23 5.55 15.73 19.58 d26 16.035.85 2.00 d31 2.63 7.22 3.89 d34 20.89 32.28 41.83 d42 2.15 10.15 36.77d45 32.42 77.43 98.47 d47 1.13 1.13 1.13 Starting Focal Lens UnitSurface Length ZOOM LENS UNIT DATA 1 1 223.82 2 7 −35.08 3 18 94.97 4 24−128.75 5 27 40.99 6 32 −48.23 7 35 249.80 8 43 249.16 9 46 ∞

[NUMERICAL EXAMPLE 5] Unit: mm Surface number r d nd vd SURFACE DATA  1∞ 1.80  2 223.328 4.00 1.80610 33.3  3 132.423 11.89 1.49700 81.5  4−1247.019 0.20  5 122.522 8.19 1.49700 81.5  6 499.314 (variable)  7187.138 2.40 1.89190 37.1  8 27.309 10.60  9 −142.381 2.00 1.89190 37.110 124.731 0.20 11 58.038 9.59 1.84666 23.8 12 −55.640 0.70 13 −50.9062.01 1.89190 37.1 14 119.208 0.20 15 67.622 6.01 1.72825 28.5 16−107.389 2.01 1.90366 31.3 17 249.755 (variable) 18 (diaphragm) ∞ 1.5019 48.129 4.04 1.78472 25.7 20 −1118.112 0.20 21* 26.402 5.86 1.4970081.5 22 785.851 2.38 1.85478 24.8 23 26.820 (variable) 24 −98.798 3.831.60738 56.8 25 −28.130 1.30 1.59522 67.7 26 282.952 (variable) 27105.994 3.98 1.72000 46.0 28 −68.403 0.20 29 51.096 6.32 1.59522 67.7 30−37.214 1.50 1.90366 31.3 31 −155.337 (variable) 32 −98.441 4.86 1.8466623.8 33 −21.653 1.30 1.80610 33.3 34 76.500 (variable) 35 97.831 1.601.80518 25.4 36 51.214 4.96 1.53172 48.8 37 −202.579 0.20 38 95.176 3.501.51633 64.1 39 −244.547 (variable) 40 912.738 1.60 1.90366 31.3 4142.335 1.77 1.74077 27.8 42 48.385 (variable) 43 128.540 1.60 1.5377574.7 44 42.172 5.08 1.74077 27.8 45 444.091 (variable) 46 ∞ 2.00 1.5163364.1 47 ∞ (variable) Image Plane ∞ ASPHERICAL SURFACE DATA 21st surfaceK = 0.00000e+000 A 4 = −1.50048e−007 A 6 = 2.39227e−010 A 8 =1.03096e−012 VARIOUS DATA Zoom Ratio 19.20 Wide-Angle Middle TelephotoFocal Length: 30.50 300.82 585.58 Fno: 4.00 6.76 8.00 Half Angle of View(°): 35.35 4.11 2.12 Image Height: 21.64 21.64 21.64 Overall LensLength: 289.33 402.18 469.33 BF: 35.16 78.40 97.38 d 6 1.20 121.18140.76 d17 82.16 8.59 2.79 d23 5.50 14.07 16.99 d26 13.49 4.92 2.00 d312.28 5.17 4.43 d34 21.20 21.20 61.71 d39 5.14 20.71 7.87 d42 3.82 8.5616.02 d45 32.71 75.95 94.93 d47 1.13 1.13 1.13 Lens Unit StartingSurface Focal Length ZOOM LENS UNIT DATA  1 1 211.86  2 7 −30.63  3 1893.83  4 24 −127.34  5 27 37.97  6 32 −57.11  7 35 77.77  8 40 −54.96  943 135.88 10 46 ∞

Table 1 indicates a relationship between each of the above inequalitiesand each numerical example.

TABLE 1 NUMERICAL EXAMPLES 1 2 3 4 5 Exp. 1 ft/|f2| 6.72 6.1 6.73 6.386.92 Exp. 2 m1/f1 0.8 0.81 0.8 0.78 0.85 Exp. 3 fr/|f2| 4.45 3.79 4.674.25 4.49 Exp. 4 f1/f3 2.46 2.26 2.53 2.36 2.26 Exp. 5 |f2|/f3 0.37 0.370.38 0.37 0.33 Exp. 6 f2/ff 0.59 0.59 0.6 0.73 0.54 Exp. 7 |f2|/skw 1.151.03 0.9 1.01 0.87 Exp. 8 f3/skw 3.14 2.78 2.38 2.72 2.67 Exp. 9 f2/fsi0.26 0.27 0.25 0.27 0.24 Exp. 10 f1/ft 0.39 0.38 0.38 0.38 0.36 Exp. 11|f2|/fw 1.1 1.19 1.08 1.15 1 Exp. 12 f3/ft 0.16 0.17 0.15 0.16 0.16 fw30.5 30.5 30.5 30.5 30.5 ft 585 585 585 585 585.58 skw 29.33 35.46 36.6934.87 35.16 f1 225.8 222.09 221.6 223.82 211.86 f2 −33.6 −36.4 −32.93−35.08 −30.63 f3 91.96 98.44 87.5 94.97 93.83 f4 −128.56 −136.57 −133.21−128.75 −127.34 f5 42.29 42.9 40.75 40.99 37.97 f6 −56.75 −6.2.12 −54.8−48.23 −57.11 f7 67.68 312.95 87.57 249.8 77.77 f8 −69.76 — −69.75249.16 −54.96 f9 — — 234.68 — 135.88 fr 149.67 138.01 153.62 149.23137.44 ml 179.76 180 176.51 173.91 180 ff −56.75 −62.12 −54.8 −48.23−57.11

According to each example, it is possible to realize a small-sized zoomlens having both a high zoom ratio and good optical performance.

While the disclosure has been described with reference to exemplaryembodiments, it is to be understood that the disclosure is not limitedto the disclosed exemplary embodiments. The scope of the followingclaims is to be accorded the broadest interpretation so as to encompassall such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No.2020-132328, filed on Aug. 4, 2020 which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A zoom lens including, in order from an objectside to an image side, a first lens unit having a positive refractivepower, a second lens unit having a negative refractive power, a thirdlens unit having a positive refractive power, and a rear unit thatincludes a plurality of lens units having negative refractive powers anda plurality of lens units having positive refractive powers, eachdistance between adjacent lens units changing during zooming, whereinduring zooming from a wide-angle end to a telephoto end, the first lensunit moves to the object side, and the second lens unit moves to theimage side and thereafter moves to the object side, and whereinfollowing inequalities are satisfied:5.50<f1/|f2|<7.500.56<m1/f1<1.19 where f1 represents a focal length of the first lensunit, f2 represents a focal length of the second lens unit, and m1represents a moving amount of the first lens unit during zooming fromthe wide-angle end to the telephoto end.
 2. The zoom lens according toclaim 1, wherein a following inequality is satisfied:2.71<fr/|f2|<6.53 where fr represents a combined focal length of therear unit at the wide-angle end.
 3. The zoom lens according to claim 1,wherein a following inequality is satisfied:1.61<f1/f3<3.55 where f3 represents a focal length of the third lensunit.
 4. The zoom lens according to claim 1, wherein a followinginequality is satisfied:0.23<|f2|/f3<0.53 where f3 represents a focal length of the third lensunit.
 5. The zoom lens according to claim 1, wherein a followinginequality is satisfied:0.38<f2/ff<1.02 where ff represents a focal length of a lens unit havinga focal length of a smallest absolute value in the plurality of lensunits having the negative refractive powers.
 6. The zoom lens accordingto claim 1, wherein a following inequality is satisfied:0.62<|f2|/skw<1.60 where skw represents a back focus at the wide-angleend.
 7. The zoom lens according to claim 1, wherein a followinginequality is satisfied:1.70<f3/skw<4.39 where f3 represents a focal length of the third lensunit and skw represents a back focus at the wide-angle end.
 8. The zoomlens according to claim 1, wherein a following inequality is satisfied:0.17<f2/fsi<0.38 where fsi represents a focal length of a lens unithaving a negative refractive power closest to a diaphragm in the rearunit.
 9. The zoom lens according to claim 1, wherein a followinginequality is satisfied:0.26<f1/ft<0.54 where ft represents a focal length of the zoom lens atthe telephoto end.
 10. The zoom lens according to claim 1, wherein afollowing inequality is satisfied:0.72<|f2|/fw<1.67 where fw represents a focal length of the zoom lens atthe wide-angle end.
 11. The zoom lens according to claim 1, wherein afollowing inequality is satisfied:0.11<f3/ft<0.24 where f3 represents a focal length of the third lensunit, and ft represents a focal length of the zoom lens at the telephotoend.
 12. The zoom lens according to claim 8, wherein during imagestabilization, the lens unit having the negative refractive powerclosest to the diaphragm in the rear unit moves in a direction includinga component of a direction orthogonal to an optical axis.
 13. The zoomlens according to claim 5, wherein during focusing, the lens unit havingthe focal length of the smallest absolute value in the plurality of lensunits having the negative refractive powers moves.
 14. The zoom lensaccording to claim 1, wherein during zooming from the wide-angle end tothe telephoto end, all the lens units included in the rear unit move tothe object side.
 15. The zoom lens according to claim 1, wherein therear unit includes, in order from the object side to the image side, afourth lens unit having a negative refractive power, a fifth lens unithaving a positive refractive power, a sixth lens unit having a negativerefractive power, and a seventh lens unit having a positive refractivepower.
 16. The zoom lens according to claim 1, wherein the rear unitincludes, in order from the object side to the image side, a fourth lensunit having a negative refractive power, a fifth lens unit having apositive refractive power, a sixth lens unit having a negativerefractive power, a seventh lens unit having a positive refractivepower, and an eighth lens unit having a negative refractive power. 17.The zoom lens according to claim 1, wherein the rear unit includes, inorder from the object side to the image side, a fourth lens unit havinga negative refractive power, a fifth lens unit having a positiverefractive power, a sixth lens unit having a negative refractive power,a seventh lens unit having a positive refractive power, an eighth lensunit having a negative refractive power, and a ninety lens unit having apositive refractive power.
 18. The zoom lens according to claim 1,wherein the rear unit includes, in order from the object side to theimage side, a fourth lens unit having a negative refractive power, afifth lens unit having a positive refractive power, a sixth lens unithaving a negative refractive power, a seventh lens unit having apositive refractive power, and an eighth lens unit having a positiverefractive power.
 19. The zoom lens according to claim 15, wherein thefourth lens unit is disposed on a position closest to a diaphragm in therear unit.
 20. An image pickup apparatus comprising: the zoom lensaccording to claim 1; and a sensor configured to receive light of animage formed by the zoom lens.